October 19, 2021
Vehicles with GM 4L60-E, 4L65-E or 4L70-E transmissions can experience light throttle shifts and poor shift quality as well as early 2-4 band failure. These problems can occur due to sleeve wear allowing torque signal and/or accumulator pressure leakage, sticking valves or using the incorrect accumulator valve ratio for the application.
The 4L60-E series valve train has three OE size variations; CX, DX, and YZ. The size variations are clearly stamped with the letters on the aluminum sleeve. The most commonly found size is the DX. However, these versions are not available unless scavenged from other valve bodies. Sonnax accumulator valve train kit 77754-10K is specifically designed for the DX size with additional selective springs to cover the CX and YZ sizes.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.